Computed Tomography (CT) is a major tool in diagnostic imaging. X-ray detection technology typically uses energy-integrating detectors that add electrical signals, from interactions between an X-ray beam and a material of the detector, over the whole spectrum. Energy-integrating detectors often lose spectral information. Spectral CT (SCT) has advantages over conventional CT by offering detailed spectral information for material decomposition. SCT can also reduce beam-hardening artifacts and radiation dose. However, related art SCT is slower, less stable, and much more expensive than conventional CT.
Conventional CT is based on energy-integrating and/or current-integrating detectors for data acquisition. With photon-counting detectors, SCT can offer additional spectral information for diagnosis, such as discriminating tissues and differentiating calcium and iodine. Related art commercial dual-energy CT technologies include a dual-source CT system from Siemens, a dual-kVp system from GE, and a dual-layer-detector-based system from Philips. These scanners are not for SCT systems because only two material basis functions can be extracted.